Mobile terminal

ABSTRACT

A mobile terminal comprises a first frame, a second frame slidably moves with respect to the first frame in a first direction to switch from a first state to a second state and in a second direction, to switch the second state to the first state, and a driving unit configured to control a slide movement of the second frame, wherein the driving unit includes a motor coupled to the first frame, a pinion gear rotated by a rotational force transferred from the motor, a first rack gear extended in the first direction, moving in the first direction or the second direction in accordance with rotation of the pinion gear, and a second rack gear disposed to be overlapped with the first rack gear in a thickness direction at the first state and disposed to release an overlap state with the first rack gear at the second state.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119 (a), this application claims the benefit ofan earlier filing date and right of priority to InternationalApplication No. PCT/KR2020/009767 filed on Jul. 24, 2020, the contentsof which are hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a mobile terminal, and moreparticularly, to a mobile terminal that has a flexible display and iscapable of extending a size of a screen while the display is scrolledand slid at the same time.

Discussion of the Related Art

Terminals may be generally classified as mobile/portable terminals orstationary terminals according to their mobility. Mobile terminals mayalso be classified as handheld terminals or vehicle mounted terminalsaccording to whether or not a user can directly carry the terminal.

In recent years, because of a development of a broadcasting technologyand a network technology, functions of the display device have also beenconsiderably diversified, and a performance of the device has beenimproved accordingly. That is, the display device has been developed toprovide not only broadcast contents but also various other contents tothe user. For example, the display device may provide game play, musiclistening, internet shopping, user customized information, and the likeusing various applications as well as programs received from thebroadcasting station. In order to perform such extended functions, thedisplay device may be basically connected to other devices or networksusing various communication protocols, and may provide the user with aubiquitous computing environment. In other words, the display device hasevolved into a smart device that enables connectivity to a network andcontinuous computing.

Recently, a flexible display having sufficient elasticity and capable oflarge deformation has been developed. The size of a mobile terminal canbe varied using the deformable nature of the flexible display. For themobile terminal having such a variable structure, changing the size ofthe mobile terminal should be stably performed, and there is a need fora structure to support the extended display unit to maintain a flatstate of the display unit.

SUMMARY OF THE INVENTION

Accordingly, the present disclosure is directed to a mobile terminalthat substantially obviates one or more problems due to limitations anddisadvantages of the related art.

One object of the present disclosure is to provide a mobile terminalthat comprises a driving unit for enlarging an extensible area.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amobile terminal comprises a first frame, a second frame configured toslidably move with respect to the first frame in a first direction toswitch from a first state to a second state and in a second direction,which is an opposite direction of the first direction, to switch thesecond state to the first state, and a driving unit configured tocontrol a slide movement of the second frame, wherein the driving unitincludes a motor coupled to the first frame, a pinion gear rotated by arotational force transferred from the motor, a first rack gear extendedin the first direction, moving in the first direction or the seconddirection in accordance with rotation of the pinion gear, and a secondrack gear disposed to be overlapped with the first rack gear in athickness direction at the first state and disposed to release anoverlap state with the first rack gear at the second state.

The second rack gear may further include a rack guide protrusionprotruded in a third direction perpendicular to a moving direction ofthe second rack gear, and may further include a rack guide rail intowhich the rack guide protrusion of the second rack gear is inserted, andextended in the first direction, and the rack guide rail may include ahorizontal portion and an inclined portion extended from an end portionof the horizontal portion to form a slope.

The rack guide protrusion may be formed at each of end portions of thesecond rack gear, and the rack guide rail may be provided as a pair ofrack guide rails spaced apart from each other in the first direction.

The rack guide protrusion and the rack guide rail may respectively beformed in third and fourth directions vertical to the first direction ofthe second rack gear.

If the first rack gear moves in the first direction and thus its overlapstate with the second rack gear is released, the rack guide protrusionmay move along the inclined portion and then may be arranged at the sameheight as the second rack gear in a thickness direction.

The mobile terminal may further comprise a pusher for pushing the secondrack gear in the first direction to allow the second rack gear to movealong the inclined portion.

The pusher may include an elastic portion arranged at the end portion ofthe second rack gear in the second direction, having a variable length.

A first fastening unit arranged at the end portion of the first rackgear in the second direction and a second fastening unit arranged at theend portion in the first direction of the second rack gear may becoupled with each other to form a continuous rack gear.

The first fastening unit may include a first fastening sawtooth arrangedat the end portion of the first rack gear in the second direction, and afastening groove arranged in the first direction of the fasteningsawtooth, and the second fastening unit may include a second fasteningsawtooth arranged at the end portion of the second rack gear in thefirst direction and coupled to be overlapped with the fastening grooveand a fastening hole into which the first fastening sawtooth isinserted.

The first rack gear and the second rack gear may each comprise asawtooth portion provided with a plurality of sawteeth and edge portionsarranged at both sides of the sawtooth portion. One of the firstfastening unit and the second fastening unit may include an edgeprotrusion instead of the edge portion, and the other one of the firstfastening unit and the second fastening unit may include an edge grooveprovided at the edge portion such that the first fastening unit and thesecond fastening unit are fastened by the edge protrusion and the edgegroove.

The first fastening unit may include first coupling sawteeth smallerthan a plurality of sawteeth of the first rack gear, and the secondfastening unit may further include second coupling sawteeth providedwith a groove coupled to the first coupling sawteeth, having the samesize as that of the plurality of sawteeth.

The first fastening unit and the second fastening unit may includemagnets having their respective polarities different from each other.

The mobile terminal may further comprise a coupling member having oneend coupled to the first rack gear and the other end coupled to thesecond rack gear, bent when the first rack gear and the second rack gearare overlapped with each other, forming a straight line in the firstdirection when the first rack gear and the second rack gear are disposedin parallel in the first direction.

A sawteeth pitch of the first rack gear and a sawteeth pitch of thesecond rack gear may be equal to each other.

Since the mobile terminal of the present disclosure may control a sizeof a screen if necessary, both portability and usability may befulfilled.

A length of the rack gear may be obtained to enlarge an extended area ofthe mobile terminal.

Serial arrangement or overlap arrangement in a thickness direction of apair of rack gears are automatically performed to facilitate a statechange of the mobile terminal.

Further scope of applicability of the present disclosure will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the disclosure, aregiven by illustration only, since various changes and modificationswithin the spirit and scope of the disclosure will become apparent tothose skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description given herein below and the accompanying drawings,which are given by illustration only, and thus are not limitative of thepresent disclosure.

FIG. 1 is a block diagram of a mobile terminal in accordance with thepresent disclosure.

FIG. 2 is a front view of a first state and a second state of the mobileterminal in accordance with an embodiment.

FIG. 3 is a rear view of the first state and the second state of themobile terminal in accordance with an embodiment.

FIGS. 4 and 5 are exploded perspective views of the mobile terminal inaccordance with an embodiment.

FIG. 6 is a side view of the mobile terminal as viewed from a thirddirection.

FIG. 7 is a view showing a driving unit of the mobile terminal inaccordance with an embodiment.

FIG. 8 is a cross-sectional view taken along lines A-A and B-B in FIG.2.

FIG. 9 is a view illustrating a display unit and a rolling plate of themobile terminal in accordance with an embodiment.

FIGS. 10 and 11 are views illustrating an extensible range of the mobileterminal.

FIG. 12 is a view illustrating a first state of a driving unit accordingto an embodiment of the present disclosure.

FIG. 13 is a view illustrating a second state of a driving unit of FIG.12.

FIG. 14 is a view illustrating a fastening process of a first rack gearto a second rack gear in the driving unit of FIG. 12.

FIG. 15 is a view illustrating a fastening process of a first rack gearto a second rack gear in the driving unit of FIG. 12.

FIGS. 16 to 21 are views illustrating embodiments of a fastening methodof a first rack gear to a second rack gear.

DETAILED DESCRIPTION OF THE INVENTION

Description will now be given in detail according to exemplaryembodiments disclosed herein, with reference to the accompanyingdrawings. For the sake of brief description with reference to thedrawings, the same or equivalent components may be provided with thesame reference numbers, and description thereof will not be repeated. Ingeneral, a suffix such as “module” and “unit” may be used to refer toelements or components. Use of such a suffix herein is merely intendedto facilitate description of the specification, and the suffix itself isnot intended to give any special meaning or function. In the presentdisclosure, that which is well-known to one of ordinary skill in therelevant art has generally been omitted for the sake of brevity. Theaccompanying drawings are used to help easily understand varioustechnical features and it should be understood that the embodimentspresented herein are not limited by the accompanying drawings. As such,the present disclosure should be construed to extend to any alterations,equivalents and substitutes in addition to those which are particularlyset out in the accompanying drawings.

It will be understood that although the terms first, second, etc. may beused herein to describe various elements, these elements should not belimited by these terms. These terms are generally only used todistinguish one element from another.

It will be understood that when an element is referred to as being“connected with” another element, the element can be directly connectedwith the other element or intervening elements may also be present. Incontrast, when an element is referred to as being “directly connectedwith” another element, there are no intervening elements present.

A singular representation may include a plural representation unless itrepresents a definitely different meaning from the context.

Terms such as “include” or “has” are used herein and should beunderstood that they are intended to indicate an existence of severalcomponents, functions or steps, disclosed in the specification, and itis also understood that greater or fewer components, functions, or stepsmay likewise be utilized.

FIG. 1 is a block diagram of a mobile terminal in accordance with thepresent disclosure.

The mobile terminal 100 is shown having components such as a wirelesscommunication unit 110, an input unit 120, a sensing unit 140, an outputunit 150, an interface unit 160, a memory 170, a controller 180, and apower supply unit 190. Referring now to FIG. 1, the mobile terminal 100is shown having wireless communication unit 110 configured with severalcommonly implemented components. It is understood that implementing allof the illustrated components is not a requirement, and that greater orfewer components may alternatively be implemented.

More specifically, the wireless communication unit 110 typicallyincludes one or more modules which permit communications such aswireless communications between the mobile terminal 100 and a wirelesscommunication system, communications between the mobile terminal 100 andanother mobile terminal, communications between the mobile terminal 100and an external server. Further, the wireless communication unit 110typically includes one or more modules which connect the mobile terminal100 to one or more networks.

To facilitate such communications, the wireless communication unit 110includes one or more of a broadcast receiving module 111, a mobilecommunication module 112, a wireless Internet module 113, a short-rangecommunication module 114, and a location information module 115.

Regarding the wireless communication unit 110, the broadcast receivingmodule 111 is typically configured to receive a broadcast signal and/orbroadcast associated information from an external broadcast managingentity via a broadcast channel. The broadcast channel may include asatellite channel, a terrestrial channel, or both. In some embodiments,two or more broadcast receiving modules 111 may be utilized tofacilitate simultaneously receiving of two or more broadcast channels,or to support switching among broadcast channels.

The mobile communication module 112 can transmit and/or receive wirelesssignals to and from one or more network entities. Typical examples of anetwork entity include a base station, an external mobile terminal, aserver, and the like. Such network entities form part of a mobilecommunication network, which is constructed according to technicalstandards or communication methods for mobile communications (forexample, Global System for Mobile Communication (GSM), Code DivisionMulti Access (CDMA), CDMA2000 (Code Division Multi Access 2000), EV-DO(Enhanced Voice-Data Optimized or Enhanced Voice-Data Only), WidebandCDMA (WCDMA), High Speed Downlink Packet access (HSDPA), HSUPA (HighSpeed Uplink Packet Access), Long Term Evolution (LTE), LTE-A (Long TermEvolution-Advanced), and the like).

Examples of wireless signals transmitted and/or received via the mobilecommunication module 112 include audio call signals, video (telephony)call signals, or various formats of data to support communication oftext and multimedia messages.

The wireless Internet module 113 is configured to facilitate wirelessInternet access. This module may be internally or externally coupled tothe mobile terminal 100. The wireless Internet module 113 may transmitand/or receive wireless signals via communication networks according towireless Internet technologies.

Examples of such wireless Internet access include Wireless LAN (WLAN),Wireless Fidelity (Wi-Fi), Wi-Fi Direct, Digital Living Network Alliance(DLNA), Wireless Broadband (WiBro), Worldwide Interoperability forMicrowave Access (WiMAX), High Speed Downlink Packet Access (HSDPA),HSUPA (High Speed Uplink Packet Access), Long Term Evolution (LTE),LTE-A (Long Term Evolution-Advanced), and the like. The wirelessInternet module 113 may transmit/receive data according to one or moreof such wireless Internet technologies, and other Internet technologiesas well.

In some embodiments, when the wireless Internet access is implementedaccording to, for example, WiBro, HSDPA, HSUPA, GSM, CDMA, WCDMA, LTE,LTE-A and the like, as part of a mobile communication network, thewireless Internet module 113 performs such wireless Internet access. Assuch, the Internet module 113 may cooperate with, or function as, themobile communication module 112.

The short-range communication module 114 is configured to facilitateshort-range communications. Suitable technologies for implementing suchshort-range communications include BLUETOOTH™, Radio FrequencyIDentification (RFID), Infrared Data Association (IrDA), Ultra-WideBand(UWB), ZigBee, Near Field Communication (NFC), Wireless-Fidelity(Wi-Fi), Wi-Fi Direct, Wireless USB (Wireless Universal Serial Bus), andthe like. The short-range communication module 114 in general supportswireless communications between the mobile terminal 100 and a wirelesscommunication system, communications between the mobile terminal 100 andanother mobile terminal 100, or communications between the mobileterminal and a network where another mobile terminal 100 (or an externalserver) is located, via wireless area networks. One example of thewireless area networks is a wireless personal area networks.

The location information module 115 is generally configured to detect,calculate, derive or otherwise identify a position of the mobileterminal. As an example, the location information module 115 includes aGlobal Position System (GPS) module, a Wi-Fi module, or both. Ifdesired, the location information module 115 may alternatively oradditionally function with any of the other modules of the wirelesscommunication unit 110 to obtain data related to the position of themobile terminal. As one example, when the mobile terminal uses a GPSmodule, a position of the mobile terminal may be acquired using a signalsent from a GPS satellite. As another example, when the mobile terminaluses the Wi-Fi module, a position of the mobile terminal can be acquiredbased on information related to a wireless access point (AP) whichtransmits or receives a wireless signal to or from the Wi-Fi module.

The input unit 120 includes a camera 121 for obtaining images or video,a microphone 122, which is one type of audio input device for inputtingan audio signal, and a user input unit 123 (for example, a touch key, apush key, a mechanical key, a soft key, and the like) for allowing auser to input information. Data (for example, audio, video, image, andthe like) is obtained by the input unit 120 and may be analyzed andprocessed by controller 180 according to device parameters, usercommands, and combinations thereof.

Such cameras 121 may process image frames of still pictures or videoobtained by image sensors in a video or image capture mode. Theprocessed image frames can be displayed on the display unit 151 orstored in memory 170. In some cases, the cameras 121 may be arranged ina matrix configuration to permit a plurality of images having variousangles or focal points to be input to the mobile terminal 100. Asanother example, the cameras 121 may be located in a stereoscopicarrangement to acquire left and right images for implementing astereoscopic image.

The microphone 122 is generally implemented to permit audio input to themobile terminal 100. The audio input can be processed in various mannersaccording to a function being executed in the mobile terminal 100. Ifdesired, the microphone 122 may include assorted noise removingalgorithms to remove unwanted noise generated in the course of receivingthe external audio.

The user input unit 123 is a component that permits input by a user.Such user input may enable the controller 180 to control operation ofthe mobile terminal 100. The user input unit 123 may include one or moreof a mechanical input element (for example, a key, a button located on afront and/or rear surface or a side surface of the mobile terminal 100,a dome switch, a jog wheel, a jog switch, and the like), or atouch-sensitive input, among others. As one example, the touch-sensitiveinput may be a virtual key or a soft key, which is displayed on a touchscreen through software processing, or a touch key which is located onthe mobile terminal at a location that is other than the touch screen.On the other hand, the virtual key or the visual key may be displayed onthe touch screen in various shapes, for example, graphic, text, icon,video, or a combination thereof.

The sensing unit 140 is typically implemented using one or more sensorsconfigured to sense internal information of the mobile terminal, thesurrounding environment of the mobile terminal, user information, andthe like. For example, the sensing unit 140 may alternatively oradditionally include other types of sensors or devices, such as aproximity sensor 141 and an illumination sensor 142, a touch sensor, anacceleration sensor, a magnetic sensor, a G-sensor, a gyroscope sensor,a motion sensor, an RGB sensor, an infrared (IR) sensor, a finger scansensor, a ultrasonic sensor, an optical sensor (for example, camera121), a microphone 122, a battery gauge, an environment sensor (forexample, a barometer, a hygrometer, a thermometer, a radiation detectionsensor, a thermal sensor, and a gas sensor, among others), and achemical sensor (for example, an electronic nose, a health care sensor,a biometric sensor, and the like), to name a few. The mobile terminal100 may be configured to utilize information obtained from sensing unit140, and in particular, information obtained from one or more sensors ofthe sensing unit 140, and combinations thereof.

The output unit 150 is typically configured to output various types ofinformation, such as audio, video, tactile output, and the like. Theoutput unit 150 is shown having a display unit 151, an audio outputmodule 152, a haptic module 153, and an optical output module 154. Thedisplay unit 151 may have an inter-layered structure or an integratedstructure with a touch sensor in order to facilitate a touch screen. Thetouch screen may provide an output interface between the mobile terminal100 and a user, as well as function as the user input unit 123 whichprovides an input interface between the mobile terminal 100 and theuser.

The audio output module 152 is generally configured to output audiodata. Such audio data may be obtained from any of a number of differentsources, such that the audio data may be received from the wirelesscommunication unit 110 or may have been stored in the memory 170. Theaudio data may be output during modes such as a signal reception mode, acall mode, a record mode, a voice recognition mode, a broadcastreception mode, and the like. The audio output module 152 can provideaudible output related to a particular function (e.g., a call signalreception sound, a message reception sound, etc.) performed by themobile terminal 100. The audio output module 152 may also be implementedas a receiver, a speaker, a buzzer, or the like.

A haptic module 153 can be configured to generate various tactileeffects that a user feels, perceive, or otherwise experience. A typicalexample of a tactile effect generated by the haptic module 153 isvibration. The strength, pattern and the like of the vibration generatedby the haptic module 153 can be controlled by user selection or settingby the controller. For example, the haptic module 153 may outputdifferent vibrations in a combining manner or a sequential manner.

An optical output module 154 can output a signal for indicating an eventgeneration using light of a light source. Examples of events generatedin the mobile terminal 100 may include message reception, call signalreception, a missed call, an alarm, a schedule notice, an emailreception, information reception through an application, and the like.

The interface unit 160 serves as an interface with various types ofexternal devices that can be coupled to the mobile terminal 100. Theinterface unit 160, for example, may include any of wired or wirelessports, external power supply ports, wired or wireless data ports, memorycard ports, ports for connecting a device having an identificationmodule, audio input/output (I/O) ports, video I/O ports, earphone ports,and the like. In some cases, the mobile terminal 100 may performassorted control functions associated with a connected external device,in response to the external device being connected to the interface unit160.

The memory 170 is typically implemented to store data to support variousfunctions or features of the mobile terminal 100. For instance, thememory 170 may be configured to store application programs executed inthe mobile terminal 100, data or instructions for operations of themobile terminal 100, and the like. Some of these application programsmay be downloaded from an external server via wireless communication.Other application programs may be installed within the mobile terminal100 at time of manufacturing or shipping, which is typically the casefor basic functions of the mobile terminal 100 (for example, receiving acall, placing a call, receiving a message, sending a message, and thelike). It is common for application programs to be stored in the memory170, installed in the mobile terminal 100, and executed by thecontroller 180 to perform an operation (or function) for the mobileterminal 100.

The controller 180 typically functions to control overall operation ofthe mobile terminal 100, in addition to the operations associated withthe application programs. The controller 180 may provide or processinformation or functions appropriate for a user by processing signals,data, information and the like, which are input or output, or activatingapplication programs stored in the memory 170.

To drive the application programs stored in the memory 170, thecontroller 180 may be implemented to control a predetermined number ofthe components mentioned above in reference with FIG. 1. Moreover, thecontroller 180 may be implemented to combinedly operate two or more ofthe components provided in the mobile terminal 100 to drive theapplication programs.

The power supply unit 190 can be configured to receive external power orprovide internal power in order to supply appropriate power required foroperating elements and components included in the mobile terminal 100.The power supply unit 190 may include a battery, and the battery may beconfigured to be embedded in the terminal body, or configured to bedetachable from the terminal body.

Some or more of the components may be operated cooperatively to embodyan operation, control or a control method of the mobile terminal inaccordance with embodiments of the present disclosure. Also, theoperation, control or control method of the mobile terminal may berealized on the mobile terminal by driving of one or more applicationproblems stored in the memory 170.

FIG. 2 is a front view of a first state and a second state of the mobileterminal in accordance with an embodiment, and FIG. 3 is a rear view ofthe first state and the second state of the mobile terminal inaccordance with an embodiment. FIGS. 2(a) and 3(a) are views showing thefirst state in which the mobile terminal is contracted, and FIGS. 2(b)and 3(b) are views showing the second state in which the mobile terminalis extended.

As shown in the figures, the mobile terminal 100 in the first state isin a contracted position, and has a smaller size than the mobileterminal 100 in the second state. In addition, the size of the displayunit 151 positioned on the front of the mobile terminal 100 is alsosmaller than in the second state. The mobile terminal 100 in the firststate may be extended in a first direction D1 to switch to the secondstate. In the second state, as shown in FIG. 2(b), the size of themobile terminal 100 and the size of the display unit 151 positioned onthe front of the mobile terminal 100 are larger than in the first state,while the size of the display unit 151 positioned on the rear of themobile terminal 100 is reduced as shown in FIG. 3(b). That is, a part ofthe display units 151 positioned on the rear of the mobile terminal 151in the first state moves to the front of the mobile terminal 100 in thesecond state.

In the following description, the direction in which the mobile terminal100 and the display unit 151 thereof are extended or enlarged is definedas a first direction D1, and the direction in which the mobile terminalcontracts or retracts or is reduced to switch from the second state tothe first state is defined as a second direction D2. A directionperpendicular to the first and second directions D1 and D2 is defined asa third and fourth directions. Description will be made on theassumption that the first and second directions are horizontaldirections and the third and fourth directions are vertical directions.However, depending on the arrangement of the mobile terminal 100, thefirst and second directions may be vertical directions and the thirddirection may be a horizontal direction.

As such, a flexible display unit 151 which is bendable may be used asthe display unit such that the position of the display unit may bevaried. The flexible display unit 151 may be a display unit capable ofmaintaining a flat state like a conventional flat panel display andcapable of warping, bending, folding, twisting, or rolling like paper.The flexible display unit 151 refers to a display which is manufacturedon a thin and flexible substrate and is thus lightweight and robust asnot to be easily broken. The flexible display unit according the presentdisclosure may be bent in a specific direction, and may be arranged suchthat the curvature thereof may change in the first direction.

In addition, an electronic paper is a display technology to whichproperties of general ink are applied. The electronic paper may bedifferent from the conventional flat panel display in using reflectedlight. The electronic paper may change information using a twisted ballor electrophoresis using a capsule.

In a state in which the flexible display unit 151 is not deformed (e.g.,a state of having an infinite curvature radius, hereinafter referred toas a basic state), a display region of the flexible display unit 151becomes flat. In a state in which the flexible display unit 151 isdeformed by an external force from the basic state (e.g., a state ofhaving a finite radius of curvature, hereinafter referred to as adeformed state), the display region may become a curved face. As shown,information displayed in the deformation state may be visual informationoutput on the curved face. Such visual information is implemented byindependently controlling light emission of sub-pixels arranged in amatrix. The sub-pixel refers to a minimum unit for implementing onecolor. When external force is applied to the flexible display unit 151,the flexible display unit 151 may be deformed to switch from the defaultstate, which is the flat state, to a bent state, which is not the flatstate.

The flexible display unit 151 may be combined with a touch sensor toimplement a flexible touch screen. When a touch is made on the flexibletouch screen, the controller 180 (see FIG. 1) may perform controlcorresponding to such touch input. The flexible touch screen may beconfigured to detect the touch input in the deformed state as well as inthe basic state.

The touch sensor detects the touch (or touch input) applied on the touchscreen using at least one of various touch schemes such as a resistivefilm scheme, a capacitance scheme, an infrared scheme, an ultrasonicwave scheme, a magnetic field scheme, and the like.

As an example, the touch sensor may be configured to convert a change inpressure applied on a specific portion of the touch screen, capacitancegenerated at the specific portion, or the like into an electrical inputsignal. The touch sensor may be configured such that a touch objectapplying a touch on the touch screen may detect touched position andarea on the touch sensor, a pressure during the touch, a capacitanceduring the touch, and the like.

Further, the mobile terminal 100 may have a deformation detection meansfor detecting the deformation of the flexible display unit 151. Suchdeformation detection means may be included in the sensing unit 140 (seeFIG. 1).

The deformation detection means may be disposed in the flexible displayunit 151 or a case (first to second frames 101 to 102 to be describedlater) to detect information related to the deformation of the flexibledisplay unit 151. In this connection, the information related to thedeformation may include a direction in which the flexible display unit151 is deformed, a degree of the deformation, a deformed position, adeformed time, an acceleration at which the deformed flexible displayunit 151 is restored, and the like. In addition, the information relatedto the deformation may include various kinds of information that may bedetected due to the bending of the flexible display unit 151.

In addition, the controller 180 may change information displayed on theflexible display unit 151 or generate a control signal for controlling afunction of the mobile terminal 100 based on the information related tothe deformation of the flexible display unit 151 detected by thedeformation detection means.

The deformation of the flexible display unit 151 may vary depending onthe positions of the first frame 101 and the second frame 102. As shownin FIG. 2, since the bending position on the flexible display unit 151is determined according to the positions of the first frame and thesecond frame, the bending deformation position of the flexible displayunit 151 and the area thereof positioned on the front may be calculatedbased on the positions of the first frame 101 and the second frame 102in place of the deformation detection means of the flexible display unit151.

The state conversion (first or second state) of the flexible displayunit 151, i.e., the size change at the front and rear faces of themobile terminal 100 of the display unit 151 based on the size change ofthe mobile terminal 100 may be performed manually by a force applied bythe user, but may be not limited to such manual scheme. For example,when the mobile terminal 100 or the flexible display unit 151 is in thefirst state, the mobile terminal 100 or the flexible display unit 151may be converted into the second state by the user or an applicationcommand without the external force applied by the user. As such, inorder for the flexible display unit 151 to be automatically deformedwithout the external force, the mobile terminal 100 may include adriving unit 200, which will be described later.

The flexible display unit 151 of the present disclosure is bent 180degrees by rolling around a side portion of the mobile terminal 100facing in the first direction. Accordingly, based on the side portion ofthe mobile terminal 100, a part of the flexible display unit 151 isdisposed on the front of the mobile terminal 100, and the other part ofthe flexible display unit 151 is disposed on the rear of the mobileterminal 100. For simplicity, the part of the flexible display unit 151positioned on the front is called a front face, and the other part ofthe flexible display unit 151 positioned on the rear is called a rearface. As illustrated in FIG. 2, the mobile terminal may extend in thefirst direction or contract in the second direction opposite to thefirst direction. In this case, the area of the flexible display unit 151positioned on the front changes. That is, the sizes of the front faceand the rear face may be changed according to a change in the state ofthe mobile terminal.

The part of the flexible display unit 151 positioned on the front of themobile terminal 100 may be immovably fixed to the front surface of thefirst frame 101, and the other part thereof positioned on the rear ofthe mobile terminal 100 may be movably arranged on the rear of themobile terminal 100.

In addition, the flexible display unit 151 may be rolled on or releasedat the side portion in the first direction of mobile terminal.Accordingly, the rear face of the display unit 151 moves, so that thesize of the front face of the display unit 151 may be adjusted. Sincethe size of the flexible display unit 151 is determined and the flexibledisplay unit 151 is formed of one continuous body, an area of rear faceof the display unit 151 decreases as an area of the front face of thedisplay unit 151 increases. Such a display unit 151 may be rolled in asecond frame 102, which is movable relative to a first frame 101 to bedescribed later, more correctly, on one of sides of the second frame102. The display unit 151 may be withdrawn or pulled out from orinserted or pushed into the second frame 102 while being rolled in thesecond frame 102 along a moving direction of the second frame 102 toadjust the area of the display unit 151 on the front face of the mobileterminal 100. Such operation will be described in more detail belowalong with other relevant components of the mobile terminal 100.

Typically, an antenna is disposed in the case or the housing of themobile terminal 100, but a portion where the antenna is installed in thecase or the housing may be limited because of the flexible display unit151 that covers not only the front face of the mobile terminal 100 butalso the rear face thereof. For this reason, the antenna may beimplemented on the flexible display unit 151. An antenna on display(AOD) is an antenna in which a transparent film is formed by stacking anelectrode layer and a dielectric layer that have patterns engravedthereon, respectively. The antenna on display may be implemented thinnerthan an antenna implemented using a laser direct structuring (LDS)technology using a conventional copper nickel plating scheme, so thatthe antenna on display may not be exposed to the outside withoutaffecting a thickness. In addition, the antenna on display may transmitand receive a signal directly to or from the display unit 151.Accordingly, the antenna on display may be used in the mobile terminal100 in which the display unit 151 is located on the both faces of themobile terminal 100 as in the present disclosure.

FIGS. 4 and 5 are exploded perspective views of the mobile terminal inaccordance with an embodiment. FIG. 4 is an exploded perspective view ofthe mobile terminal as viewed from the front side, and FIG. 5 is anexploded perspective view of the mobile terminal as viewed from the rearside.

The mobile terminal 100 of the present disclosure includes frames 101and 102 in which components are mounted, and the frames 101 and 102 ofthe present disclosure may vary in size in the first direction as shownin FIG. 2. One or more frames 101 and 102 move relative to each other,and sizes thereof may vary in the first direction. Electronic componentsare mounted in the frames 101 and 102, and the flexible display unit 151is located out of the frames 101 and 102.

Since the mobile terminal 100 of the present disclosure includes theflexible display unit 151, the flexible display unit 151 may be combinedin a form surrounding front faces and rear faces of the frames 101 and102. The frame may include the first frame 101 and the second frame 102moving in the first direction with respect to the first frame 101. Thefirst frame 101 and the second frame 102 include front portions, a rearportions, and side portions, respectively, and are coupled to eachother.

First, the first frame 101 corresponds to a main body of the mobileterminal 100, and may have a space between the first front portion 1011and the first rear portion 1012 therein for accommodating variouscomponents. In addition, the first frame 101 may accommodate the secondframe 102 movably coupled to the first frame 101 in such a space. Morespecifically, as shown in FIGS. 2 and 5, the first frame 101 may includea first front portion 1011 disposed at a front portion of the mobileterminal 100 and supporting the front face of the display unit 151 and afirst rear portion 1012 disposed at a rear portion of the mobileterminal and on which various components are mounted. A front deco 1016may cover front edges of the first area 151 a to protect the edges ofthe first area 151 a.

The first front portion 1011 and the first rear portion 1012 may bespaced apart from each other at a predetermined spacing to define apredetermined space therebetween, and may be connected to each other bya first side portion 1013. The first side portion 1013 may be integrallyformed with the first rear portion 1012 or the first front portion 1011.The camera 121, the audio output module 152, and the input/outputterminal, the controller 180, and the power supply unit 190 may beaccommodated as components of the mobile terminal 100 in the space inthe first frame 101. For example, the controller 180 may be a circuitboard 181 including a processor and an electronic circuit forcontrolling the operation of the mobile terminal, and the power supplyunit 190 may be a battery 191 and related components. In addition, thedriving unit 200 that controls the slide movement of the second frame102, which will be described later, may also be accommodated in thefirst frame 101.

As described above, the display unit 151 has the continuous body, andthus, may be disposed on both the front face and the rear face of themobile terminal 100 while being rolled in the mobile terminal 100. Thedisplay unit 151 may include the front face positioned at the front faceof the mobile terminal 100, the rear face positioned at the rear face ofthe mobile terminal 100, and the side face positioned between the frontface and the rear face thereof and surrounding the side face of themobile terminal. The front face and the rear face of the display unit151 are flat, and the side face of the display unit 151 may form acurved face. The flexible display unit 151 may be damaged when beingbent at an angle. Thus, the flexible display unit 151 may be formed tobe bent with a predetermined curvature at the side face.

The display unit 151 may be divided into a fixed portion 151 a and 151 band a variable portion 151 c. The fixed portion 151 a and 151 b means aportion fixed to the frame. Because of being fixed to the frame, thefixed portion 151 a and 151 b maintains a constant shape withoutchanging a bending degree. On the other hand, the variable portion 151 cmeans a portion in which a bending angle or a position of the bentportion changes. The variable portion 151 c in which the position orbending angle of the bent portion changes requires a structure forsupporting a rear face of the variable portion 151 c in response to thechange.

The fixed portion 151 a, 151 b is coupled to the first frame of thedisplay unit and is always positioned on the front face of the displayunit to form a portion of the front face of the display unit. Thevariable portion 151 c includes a side face located at a side portion ofthe mobile terminal, and a position of the side face varies depending onthe position of the second frame. Based on a side face, an area of aportion disposed on the front face of the display unit and an area of aportion disposed on the rear face of the display unit vary. That is, aportion of the variable portion 151 c may be the front face and anotherportion of the variable portion 151 c may be the rear face based on thefirst and second states. The variable portion 151 c is positioned in thefirst direction with respect to the fixed portion 151 a, 151 b relativeto the mobile terminal, and an end of the variable portion 151 c is benttoward the rear face of the mobile terminal and slides on the rear faceof the second frame.

The end of the variable portion of the display unit is coupled with aslide frame that guides the variable portion to slide move on the rearface of the second frame, and the slide frame moves in the firstdirection at the same time as the second frame moves in the firstdirection. As a result, a moving distance of the slide frame withrespect to the first frame is twice as a moving distance of the secondframe with respect to the first frame. Further, as shown in FIG. 3, thefirst rear portion 1012 of the mobile terminal 100 includes an exposedrear portion 1015 that is exposed to the outside without being coveredby the display unit 151 even in the first state. The physical input unit120 for the manipulation of the mobile terminal 100 such as variousbuttons, switches, the camera 121, and a flash, and the sensing unit 140such as the proximity sensor 141 or a fingerprint sensor may be arrangedon the exposed rear portion 1015. The first rear portion 1012 except forthe exposed rear portion 1015 may be covered by the display unit 151 inthe first state as shown in FIG. 3(a), and may be exposed rearward inthe second state as shown in FIG. 3(b).

In a conventional bar-shaped terminal, a display unit is provided onlyon a front face of the terminal. Therefore, a main camera is placed on arear face of the terminal in order for the user to capture an object atan opposite side while looking through the display unit. On the otherhand, an additional auxiliary camera is required to be disposed on thefront face of the terminal in order for the user to capture himself orherself while viewing himself or herself through the display unit.

In the mobile terminal 100 of the present disclosure, on the other hand,the display unit 151 is arranged on both the front and rear of themobile terminal 100. Accordingly, when a user photographs himself, aportion of the display unit 151 positioned on the same surface as thecamera 121, that is, the rear face of the display unit 151 may be used.When the user takes a photograph of an object around the user, a portionof the display unit 151 on the side facing away from the camera 121,that is, the front face of the display unit 151 may be used. For thisreason, the mobile terminal 100 may take a photograph of the user or anobject located around the user using one camera 121. The camera mayinclude a plurality of cameras having different angles of view, such aswide angle, ultra wide angle, and telephoto angle. Not only the camerabut also a proximity sensor and an audio output unit may be disposed onthe exposed rear portion 1015, and an antenna may be installed on therear portion 1015. The rear portion 1015 may be used to protect thecamera, the sensor, or the like on the exposed rear portion 1015 and notto deteriorate the exterior design. A portion of the rear portion 1015corresponding to the camera 121 or the sensor 140 may be configured tobe transparent, and the other portion thereof may have a predeterminedpattern or color in consideration of design aspects without exposinginternal parts.

The first side portion 1013 may extend along the edges of the firstfront portion 1011 and the first rear portion 1012 to surround thecircumference of the first frame 101 and may define the appearance ofthe mobile terminal 100. However, as mentioned above, the second frame102 is accommodated in and movably coupled to the first frame 101, andtherefore a portion of the first frame 101 needs to be open to allowmovement of the second frame 102 relative to the first frame 101. As anexample, as best shown in FIG. 2, the second frame 102 may be movablycoupled to a side of the first frame 101 facing in the first direction,and accordingly the first side portion 1013 may not be formed on thelateral surface facing in the first direction such that the lateralsurface is open. Since the first side portion 1013 is exposed to theoutside of the mobile terminal 100, the interface unit 160 forconnecting a power port or an ear jack or the user input unit 120, suchas a volume control button, may be disposed on the first side portion1013. When the first side portion 1013 contains a metal material, thefirst side portion 1013 may serve as an antenna.

The second frame 102 may include a second front portion 1021 disposed atthe front portion of the mobile terminal 100 and a second rear portion1022 disposed at the rear portion of the mobile terminal 100. Like thefirst front portion 1011 and the first rear portion 1012 of the firstframe 101, the second front portion 1021 and the second rear portion1022 may be formed of plate-shaped members that are generally flat. Inaddition, the second frame 102 also accommodates various components, andmust not interfere with the components accommodated in the first frame101 during the movement. Accordingly, the second front portion 1021 andthe second rear portion 1022 may be coupled to each other in a state ofbeing spaced apart from each other to define a predetermined spacetherebetween, and may have shapes that do not interfere with thecomponents in the first frame 101.

FIG. 6 is a side view of the mobile terminal as viewed from a thirddirection. FIG. 6 shows the first side portion 1013 of the first frame101 and a second side portion 1023 of the second frame 102. Since theflexible display unit 151 is positioned at an end of the second frame102 facing in the first direction, the end of the second frame 102facing in the first direction should not be exposed to the outside. Anend of the second frame 102 facing in the second direction should beopen so as not to interfere with the first frame 101. In the firststate, the second side portion 1023 of the second frame 102, which ispositioned on the side facing in the third direction (which refers tothe upward or downward direction in the drawing or may include both theupward and downward directions), may not be exposed to the outsidebecause it overlaps the first side portion 1013 of the first frame.However, in the second state, it may be exposed to the outside becausethe second frame 102 is drawn out.

In addition, the display unit 151 may be bent 180 degrees while beingrolled in the second frame 102 to be disposed on both the front face andthe rear face of the mobile terminal 100. For such an arrangement of thedisplay unit 151, the second frame 102 may include a roller 210rotatably disposed therein. The roller 210 may be disposed at anyposition inside the second frame 102. However, the display unit 151should be spread flat on the front face and the rear face of the mobileterminal 100 to provide a good quality screen to the user. Further, forsuch spread, a proper tension must be provided on the display unit 151.In order to provide the proper tension, the roller 210 may be disposedat a first directional end of the second frame 102. The roller 210 mayextend in the third direction, and may be rotatably coupled to thesecond frame 102.

The display unit 151 may be rolled around the roller 210 while beinggently bent with a predetermined curvature. The flexible display unit151 may include a first face on which a video is output and exposed tothe outside and an inner face facing the frame at the opposite side. Theroller 210 may be installed to rotate freely in the second frame 102while being in contact with the inner face of the display unit 151.Accordingly, the roller 210 may actually move the display unit 151 in alateral direction of the mobile terminal 100, that is, in a directionperpendicular to a longitudinal direction. As will be described later,when the second frame 102 slides, because of the tension applied by thesecond frame 102, the display unit 151 moves to the front face or therear face of the mobile terminal 100 in different directions (i.e., thefirst direction D1 or the second direction D2) relative to the secondframe 102. The roller 210 may guide such movement while rotating.

The roller 210 may be disposed adjacent to the end of the second frame102 that faces in the first direction. A side frame 1024 may be disposedat the end of the second frame 102 facing in the first direction toprevent damage to the display unit 151 rolled around the roller 210.

The side frame 1024 may extend in the longitudinal direction (the thirddirection) of the second frame 102 to cover the side portion facing inthe first direction, thereby protecting the roller 210 and the displayunit 151 rolled therearound.

The side frame 1024 may substantially define the appearance of themobile terminal 100 in cooperation with the first side portion 1013 ofthe first frame 101. In addition, the side portion of the second frame102 that faces in the second direction may be omitted to minimizeinterference with the components arranged in the first frame 101 duringmovement.

During the expansion and the contraction in such first and seconddirections D1 and D2, the second frame 102 may overlap the first frame101, more precisely, the first front portion 1011 and the first rearportion 1012 thereof so as not to interfere with the first frame 101.More specifically, the display unit 151 may be coupled to and supportedby the first front portion 1011 of the first frame 101, as describedabove. Accordingly, the display unit 151 does not need to beadditionally supported by the second front portion 1021 of the secondframe 102. Rather, when the second front portion 1021 is interposedbetween the first front portion 1011 and the display unit 151, thedisplay unit 151 may be deformed or damaged because of friction with thesecond front portion 1021, which is repeatedly moved. Thus, the secondfront portion 1021 may be disposed below the first front portion 1011,or may be interposed between two first front portions 1011. The secondrear portion 1022 of the second frame 102 may be disposed rearward ofthe first rear portion 1012 of the first frame 101. That is, the frontface of the second rear portion 1022 may face the rear face of the firstrear portion 1012. In addition, the rear face of the first rear portion1012 may be in contact with the front face of the second rear portion1022 to stably support the movement of the second frame 102. Because ofsuch arrangement, the second rear portion 1022 may be exposed to theoutside of the first frame, more precisely, of the first rear portion1012, and may be coupled to the display unit 151.

In addition, the second frame 102 may extend and contract in the firstand second directions D1 and D2 to change the size of the mobileterminal 100, particularly, to extend or contract the front face of themobile terminal 100. Thus, the display unit 151 must move by suchextended or reduced front face size to obtain the intended first andsecond states. However, when being fixed to the second frame 102, thedisplay unit 151 may not be moved smoothly to be adapted for the frontface of the mobile terminal 100 that is extended or contracted. For thisreason, the display unit 151 may be movably coupled to the second frame102.

More specifically, the display unit 151 may include a first region 151 adisposed on the front of the mobile terminal 100, a second region 151 bcoupled to a slide frame 103 positioned on the rear of the mobileterminal 100, and a third region 151 c located between the first region151 a and the second region 151 b and bent around the roller 210. Thethird region 151 c may move to the front or the rear according to changein the state of the mobile terminal 100. The slide frame 103 may beformed of a plate-shaped member extending in the longitudinal direction(the third direction) of the mobile terminal 100, and may be coupled tothe second rear portion 1022 so as to be movable in the first and seconddirections D1 and D2.

The first to third regions 151 a, 151 b, and 151 c may be connected toeach other, and may form a continuous body of the display unit 151. Inaddition, as described above, for the movement of the third region 151 ctoward the front face or the rear face of the mobile terminal 100depending on the moving direction of the second frame 102, the firstregion 151 a may be fixed so as not to move to the front face of themobile terminal 100, and the second region 151 b may be provided to bemovable on the rear face of the mobile terminal. Such configuration ofthe display unit 151 will be described in more detail below.

The first region 151 a may be disposed on the front face of the mobileterminal 100, more specifically, the first frame 101, that is, on thefront face of the first front portion 1011. The first region 151 a isfixed to the first frame 101, that is, the front face of the first frontportion 1011 so as not to be moved during the movement of the secondframe 102, and thus, the first region 151 a may always be exposed to thefront face of the mobile terminal 100.

The third region 151 c may be disposed to adjoin a first direction ofthe first region 151 a and extended in a rear direction by being rolledon the roller 210. The third region 151 c arranged in the rear directionmay cover the second frame 102, that is, the rear surface of the secondrear portion 1022. Meanwhile, since the second frame 102, that is, thesecond rear portion 1022 is adjacent to the first frame 101, that is,the first rear portion 1012 and forms the rear case of the mobileterminal 100 together with the first rear portion 1012, it may beconsidered that the third region 151 c is also disposed on the rearsurface of the first frame 101.

The second region 151 b may be adjacent to the third region 151 c andmay be disposed on the rear face of the mobile terminal 100, morespecifically, on the second frame 102, that is, the rear face of thesecond rear portion 1022 thereof. The second region 151 b may be coupledto the slide frame 103 without being directly coupled to the secondframe 102.

As a result, the first region 151 a may be disposed on the front face ofthe mobile terminal 100 and may be always exposed to the front faceregardless of the movement of the second frame 102, and the secondregion 151 b may be disposed on the rear face of the mobile terminal 100and may be always exposed to the rear face regardless of the movement ofthe second frame 102. In addition, the third region 151 c may bedisposed between the first and second regions 151 a and 151 b, and maybe selectively placed on the front face or the rear face of the mobileterminal 100 depending on the moving directions D1 and D2 of the secondframe 102.

Because of such selective placement of the third region 151 c, the firstrear portion 1012 of the first frame 101 may be exposed to the outsideof the mobile terminal 100 because the first rear portion 1012 iscovered by the second and third regions 151 b and 151 c and the secondrear portion 1022 of the display unit 151 in the first state, but, inthe second state, the third region 151 c moves to the front face of themobile terminal 100 and the second rear portion 1022 also moves in thefirst direction D1. In addition, the second front portion 1021 of thesecond frame 102 is hidden by the first front portion 1011 of the firstframe 101 in the first state, but, in the second state, moves out of thefirst frame 101 to support the third region 151 c of the display unit151 disposed on the front face of the mobile terminal 100.

In order to prevent the second front portion 1021 from affecting theinternal components during the slide movement, a separating plate 1017may be further disposed rearward of the second front portion 1021 andfastened with the first front portion 1011. The second front portion1021 may move between the first front portion 1011 and the separatingplate 1017 based on the slide movement of the second frame.

However, the third region 151 c may be rolled on the roller 210 and bentin the second frame 102. When converting from the first state to thesecond state, the third region 151 c may extend from the second frame102 to the front face of the mobile terminal 100 while being rolled onthe roller 210 in one direction. On the other hand, when converting fromthe second state to the first state, the third region 151 c may beretracted from the front face of the mobile terminal 100 to the secondframe 102 while being rolled on the roller 210 in the oppositedirection, and at the same time, may return to the rear face of themobile terminal 100 from the second frame 102.

A specific location of the foldable mobile terminal in a form of beingspread like a book is easily damaged because only the specific locationis folded repeatedly. On the other hand, the deformed portion of theflexible display unit 151, that is, a portion rolled on the roller 210,may vary based on the first and second states of the mobile terminal100, that is, the movement of the second frame 102. Accordingly, themobile terminal 100 of the present disclosure may significantly reducedeformation and fatigue repeatedly applied to a specific portion of thedisplay unit 151, thereby preventing damage to the display unit 151.

Based on the above-described configuration, overall operations of themobile terminal 100 will be described as follows. As an example, thestate conversion may be performed manually by the user, and an operationof the mobile terminal 100 during such manual state conversion will bedescribed. However, operations of the first to third frames 101 to 103and the display unit 151, which will be described below, may beperformed in the same manner when a power source other than a user'sforce is used, for example, when the driving unit 200 to be describedbelow is applied.

A rear face cover 1025 may be further disposed on a rear face of thesecond rear portion 1022 such that the rear face of the display unitpositioned on the rear face of the mobile terminal 100 is not exposed tothe outside. The rear face of the display unit may be used in the firststate when the rear face cover 1025 uses a transparent material, and therear face of the display unit may be covered such that the movement ofthe slide frame 103 is not exposed when the rear face cover 1025 uses anopaque material. That is, the second region and the third region of theslide frame 103 and the display unit 151 may move in the first directionand in the second direction in a space between the second rear portion1022 and the rear face cover 1025.

FIG. 7 is a view showing a driving unit 200 of the mobile terminal 100in accordance with an embodiment. FIG. 7(a) shows the first state andFIG. 7(b) shows the second state. The mobile terminal 100 of the presentdisclosure may be switched between the states in a manner in which auser manually pulls the second frame 102 in the first direction D1 orpushes the same in the second direction D2 with respect to the firstframe 101. However, in the manual method, applying excessive force tothe body of the mobile terminal 100 may damage the mobile terminal 100.Accordingly, a driving unit 200 employing a motor 201 may be furtherprovided to cause the second frame 102 to stably move withoutdistortion.

As the motor 201, a motor 201 configured to provide rotational force asshown in FIG. 7, or a linear motor 201 configured to make linear motionmay be used. The motor 201 configured to provide the rotational forceshould have a large diameter to provide large force. Two motors 201 maybe used as shown in FIG. 7 to provide driving force of a predeterminedmagnitude or more in the limited space of the mobile terminal 100without increasing the thickness.

If the second frame 102 is moved excessively fast, damage or malfunctionmay occur. Accordingly, a planetary gear configured to decrease thespeed of the motor 201 to ensure movement at a stable speed may befurther provided. The planetary gear 202 serves to amplify or attenuatethe number of revolutions of the motor 201 using a plurality of discgears having different numbers of teeth. The motor 201 may be fixed tothe first frame 101 as shown in FIG. 7(a). The position of the motor 201is fixed even when the second frame 102 moves in the first direction toswitch the mobile terminal 100 to the second state, as shown in FIG.7(b).

Since the second frame 102 linearly moves with respect to the firstframe 101 in the first direction or the second direction, rack andpinion gears configured to convert the rotational force of the motor 201into linear motion may be used. A pinion gear to receive the rotationalforce of the motor 201 may be arranged to engage with a rack gear 205composed of teeth continuously arranged in the first direction. Thepinion gear may be fixed to the first frame 101 together with the motor201 and the rack gear 205 may be positioned on the second frame 102.Alternatively, the rack gear 205 may be positioned on the first frame101, and the motor 201 and the pinion gear may be arranged on the secondframe 102. Since the motor 201 holds the pinion gear such that thepinion gear does not rotate, the second frame 102 may maintain the firststate and the second state. However, when large external force isapplied, the second frame 102 may be displaced as the pinion gearrotates.

A stopper (not shown) configured to fix the positions of the secondframe 102 or the rack gear 205 and the first frame 101 may be furtherprovided to fix the mobile terminal 100 in the first state or the secondstate. When electric current flows through the motor 201 to drive themotor 201, the stopper may be released to allow the movement of thesecond frame 102. When power is not applied to the motor 201 and thusthe motor 201 does not rotate, the first frame 101 and the second frame102 may be fastened such that the positions thereof are fixed.

When a pair of driving units 200 is symmetrically disposed in thevertical direction (the third direction), stable movement may be made.However, to arrange a battery or the like, the driving unit 200 shouldbe arranged biased to one side in consideration of the limited mountingspace of the mobile terminal 100 as shown in FIG. 7(a). According tosuch asymmetric arrangement of the driving unit 200, the second frame102 may be distorted during movement due to a difference in movementspeed between the upper end portion and the lower end portion. Toaddress this issue, a linear guide 230 may be further provided.

The linear guide 230 may be disposed at both ends of the mobile terminal100 facing in the third direction, that is, on the upper and lower sidesof the mobile terminal 100, in order to supplement the function of onedriving unit 200 biased to one side in the third direction. The linearguide 230 may include a guide rail 231 extending in the first directionand a guide block 232 configured to move along the guide rail 231. Theguide rail 231 may be disposed on the first frame 101 and the guideblock 232 may be disposed on the second frame 102, or vice versa. Inthis embodiment, the guide rail 231 may be disposed on the second frame102 to cover the upper and lower sides of the extended portion of thesecond frame 102 in the second state.

After the guide block 232 is coupled to the first frame 101 and theguide rail 231 is coupled to the second frame 102, the guide block 232and the guide rail 231 may be slidably fastened to each other. However,for convenience of the fastening, the guide block 232 and the guide rail231 fastened to each other. Then, the guide block 232 may be first fixedto the first frame 101, and then the second frame 102 may be coupled tothe guide rail 231.

The guide block 232 may be provided with a guide groove into which theguide rail 231 is inserted. Alternatively, the guide rail 231 may beprovided with a rail groove into which a portion of the guide block 232is inserted. The fastening portions of the guide rail 231 and the guideblock 232 may be formed to be bumpy. Accordingly, movement in the firstdirection or the second direction may be made without displacement inthe thickness direction of the mobile terminal 100. In order to reducefriction between the guide block 232 and the guide rail 231, aself-lubricating member having high wear resistance and low frictionresistance, such as a bearing or polyoxymethylene (POM), may be added tothe inside of the guide groove.

FIG. 8 is a cross-sectional view taken along lines A-A and B-B in FIG.2. As illustrated in FIG. 2, when the second frame 102 switches to thesecond state by moving in the first direction, the third region 151 cpositioned on the rear side moves to the front, and thus a structure tosupport the rear surface of the third region 151 c moved to the front isrequired. The second front portion 1021 positioned on the front surfaceof the second frame 102 may be positioned on the rear surface of thethird region 151 c in the second state. However, in the first state, thesecond front portion 1021 is disposed to overlap the first front portion1011 of the first frame 101, and accordingly the first front portion1011 and the second front portion 1021 form a step. A boundary is formedbetween the first region 151 a and the third region 151 c of theflexible display unit 151 by the step formed by the first front portion1011 and the second front portion 1021. A rolling plate 104 may be usedas a support structure to fill the gap between the second front portion1021 and the third region 151 c of the flexible display unit 151.

The rolling plate 104 may be positioned on the rear surface of theflexible display unit 151, and have a thickness corresponding to the gapbetween the second front portion 1021 and the flexible display unit 151in the second state. As shown in FIG. 8(a), in the first state, therolling plate 104 is rolled around the roller 210 and is positioned onthe lateral side and rear side of the mobile terminal 100. The flexibledisplay unit 151 and the rolling plate 104 may be positioned between thesecond rear portion of the second frame 102 and a rear cover 1025provided to cover the rear face of the display unit 151. As shown inFIG. 8(b), when switch to the second state occurs, the rolling plate 104may move to the front and the rolling plate 104 may be positioned on thefront portion of the second frame 102.

The third region 151 c of the display unit 151 in which the rollingplate 104 is positioned is a portion where bending deformation occurswhen switch from the first state to the second state occurs.Accordingly, the rolling plate 104 may be deformed according todeformation of the third region 151 c. Here, the rolling plate 104 isrequired to have a predetermined stiffness to maintain the flat statewhen the flexible display unit 151 is positioned on the front or rear ofthe mobile terminal. That is, the rolling plate 104 needs a structurecapable of maintaining the flat state in the third direction andperforming bending deformation in the first direction.

FIG. 9 is a view illustrating a display unit 151 and a rolling plate 104of the mobile terminal 100 in accordance with an embodiment. The rollingplate 104 may include multiple support bars 1041 extending in the thirddirection. The multiple support bars 1041 may be arranged side by sidein the first direction and spaced apart from each other by apredetermined distance. Accordingly, even when the flexible display unit151 is rolled around the roller 210 and is thus bent, interferencebetween the support bars 1041 may be avoided. The support bars 1041 maybe implemented with an injection molding material having a predeterminedthickness for stiffness, and may include materials such as SUS orferrosilicon (FeSi).

The multiple support bars 1041 may be directly attached to the rearsurface of the display unit 151. However, this operation may take a longtime and produce a lot of defects, resulting in poor productivity. Inaddition, directly processing the display unit 151 is highly likely todamage the display unit 151. Therefore, a rolling sheet 1045 to fix themultiple support bars 1041 may be further provided. The rolling sheet1045 may include a metal material, and may employ a superelasticmaterial that is bending-deformable and capable of recovering the flatstate after the bending deformation. For example, a superelastic metalsheet such as a thin STS sheet of 0.05 mm or less may be used. Anadhesive tape may be attached to both surfaces of the rolling sheet 1045to bond the rolling sheet 1045 to the support bars 1041 and bond therear surface of the display unit 151 to the rolling sheet 1045.

The rolling sheet 1045 may be provided with a kerf pattern in whichmultiple grooves extending in the third direction are formed in thefirst direction. The grooves in the kerf pattern may be formed betweenthe multiple support bars 1041. The grooves may be formed on a surfaceof the rolling sheet 1045 to which the support bars 1041 are bonded. Thekerf pattern may be formed in a wedge shape that is formed by beinggradually narrowed from the surface portion of the rolling sheet 1045.

Instead of the rolling sheet 1045, an elastic material such as siliconemay be disposed between the support bars 1041 to join neighboringsupport bars 1041. In this case, the angle between the support bars 1041may be varied. The elastic connector may be bent at a positioncorresponding to the roller 210. When positioned on the front or rear ofthe mobile terminal, the elastic connector may be unfolded such that thesupport bars 1041 are disposed forming a flat surface.

The support bars 1041 may form a flat surface corresponding to the rearsurface of the display unit 151. Alternatively, as shown in FIG. 8(b),the support bars 1041 may be formed in a shape having a predeterminedcurvature. The curved support bars 1041 may closely contact the curvedsurface of the roller 210 when the rolling plate 104 is rolled aroundthe roller 210. Alternatively, one surface of the support bars 1041 incontact with the display unit 151 maintains a flat state, and the othersurface thereof on the opposite side may include a curved surfacecorresponding to the curvature of the roller 210. In this case, thesupport bars 1041 may be thick at the ends thereof facing in the firstand second directions and have the thinnest portion in the middlethereof.

The rolling plate 104 may be disposed at a position corresponding to thethird region 151 c and is rolled and bent around the roller 210. Thus,the rolling plate 104 may span over the front and rear surfaces. Therolling plate 104 is connected to the first front portion 1011 of thefirst frame 101 on the front side and connected to the slide frame 103on the rear side. In order for the flexible display unit 151 to form acontinuous surface without a step, the first front portion 1011 of thefirst frame 101 positioned on the rear surface of the first region 151a, the slide frame 103 positioned on the rear surface of the secondregion 151 b, and the rolling plate 104 positioned on the rear surfaceof the third region 151 c may be arranged such that the surfaces thereofin contact with the display unit 151 are at the same height. Inparticular, since the slide frame 103 moves on the rear of the mobileterminal 100 and moves in the same space as the rolling plate 104, therolling plate 104 may have a thickness corresponding to the thickness ofthe slide frame 103.

FIGS. 10 and 11 are views illustrating an extensible range of the mobileterminal 100.

When the second frame moves with respect to the first frame 101, theflexible display unit 151 arranged in the rear direction of the mobileterminal 100 moves to a front direction, and an area of the mobileterminal 100 is widened. At this time, a moving distance of the secondframe 102 is limited to a movable distance of the rack gear 205 of thedriving unit 200.

As shown in FIG. 11, since an actual movable distance S1 of the rackgear 205 is shorter than a length ‘r’ of the rack gear 205, a movingdistance of the second frame 102 is more restricted than a size in thefirst direction of the second frame 102.

As shown in FIG. 10(b), a length S increased in the first direction atthe second state is not longer than that at the first state. That is, anoverlap area of the first frame 101 and the second frame 102 is greateven at the second state. The driving unit 200 having a long stroke isrequired such that the second frame 102 at the second state may move inthe first direction by using a width of the second frame 102 if possibleas shown in FIG. 10(c).

The length of the rack gear 205 is limited by the length of the secondframe 102 because the rack gear 205 is coupled to the second frame 102,and the rack gear 205 should be engaged with the pinion gear 202 at boththe first state and the second state as shown in FIG. 11.

To solve the above problem, the rack gear 205 of multiple stages may beused. A stroke may be increased using a first rack gear 2051 moving by arotational force directly transferred from the motor 201 and a secondrack gear 2052 moving relatively with respect to the first rack gear2051. FIG. 12 is a view illustrating a first state of a driving unit 200according to an embodiment of the present disclosure, and FIG. 13 is aview illustrating a second state of the driving unit 200 of FIG. 12. Inthe driving unit 200 shown in FIG. 12, the first rack gear 2051 and thesecond rack gear 2052 are disposed to be overlapped with each other in athickness direction of the mobile terminal 100 at the first state of themobile terminal 100. FIG. 12(a) illustrates a front direction, and FIG.12(b) is a cross-sectional view taken along line D-D.

In the driving unit 200 shown in FIG. 13, the first rack gear 2051 andthe second rack gear 2052 are disposed in parallel in the firstdirection of the mobile terminal 100 at the second state of the mobileterminal 100. FIG. 13(a) illustrates a front direction, and FIG. 13(b)is a cross-sectional view taken along line E-E.

In the driving unit 200 of this embodiment, a pair of motors 201 may bedisposed in parallel in the first direction to enhance a driving force.If a size of the motor 201 is increased to enhance the driving force ofthe motor 201, the size of the motor 201 becomes greater than athickness of a mounting space of the mobile terminal 100, whereby it maybe difficult for the motor 201 to be mounted in the mobile terminal 100.This problem may be solved using the plurality of motors 201.

The driving unit 200 may include a pinion gear 202 rotated by a drivingforce transferred from the motor 201 and a rack gear 205 rotated to beengaged with the pinion gear 202, and may further include an planetarygear 203 to match a rotation rate of the motor 201 with a rotation rateof the pinion gear 202.

The rack gear 205 of this embodiment includes the first rack gear 2051and the second rack gear 2052, wherein the pinion gear is engaged withthe first rack gear 2051 to move the first rack gear 2051 in the firstdirection 202 at the state of FIG. 12, and the pinion gear 202 isengaged with the second rack gear 2052 to move the second rack gear 2052in the first direction at the state of FIG. 13.

If the second rack gear 2052 and the first rack gear 2051 are disposedin parallel as shown in FIG. 13, the force transferred to the secondrack gear 2052 may be transferred to the first rack gear 2051, wherebythe first rack gear 2051 and the second rack gear 2052 may movetogether.

FIG. 12(b) is a cross-sectional view taken along line C-C of FIG. 12(a).As shown in FIG. 12(b), at the first state of the mobile terminal 100,the first frame 101 and the second frame 102 may be disposed to overlapeach other in the thickness direction, a sawteeth surface of the firstrack gear 2051 and a sawteeth surface of the second rack gear 2052 maybe headed for the same direction, and a sawteeth shape (width, interval)of the second rack gear 2052 may be formed in the same as that of thefirst rack gear 2051.

As shown in FIG. 12(b), the second rack gear 2052 may be disposed to beoverlapped on the sawteeth surface of the first rack gear 2051. On thecontrary, the first rack gear 2051 may be disposed to be overlapped onthe sawteeth surface of the second rack gear 2052. In case of the formercase, a step difference should downwardly be formed on a mountingsurface of the driving housing in which the rack gear is embedded, toarrange the second rack gear 2052. A description will be given based onthe embodiment of the former case.

The driving unit 200 may include a driving housing fixed to dispose therespective elements at their exact positions and easily fastened to thefirst frame 101. The driving housing may further include a pair of rackguide walls 204 formed at both sides of the rack gear 205 to stably movethe rack gear 205. The pair of rack guide walls 204 may be spaced apartfrom each other at an interval corresponding to a width of the rack gear205, and may guide a moving direction of the rack gear 205 to move therack gear 205 in the first direction or the second direction withoutdistortion.

The second rack gear 2052 may include a rack guide protrusion 20521protruded in a direction vertical to the moving direction at the sidethereof. The rack guide protrusion 20521 may be inserted into a rackguide rail 209 formed on the rack guide wall 204 to move along the rackguide rail 209. That is, the second rack gear 2052 may move along atrack corresponding to an extended shape of the rack guide rail 209.

FIG. 14 is a view illustrating a rack guide rail 209, wherein FIG. 14(a)is a side view of FIG. 12(a), FIG. 14(b) is a side view of FIG. 13(a),and FIG. 14(c) is a cross-sectional view taken along line F-F of FIG.14(b).

Referring to FIG. 11, the rack guide rail 209 formed on the rack guidewall 204 is shown, and may include a groove shape inserted onto innersides of a pair of rack guide wall 204 or a shape passing through therack guide wall 204 as shown in FIG. 14.

The rack guide rail 209 includes a horizontal portion 209 b extended inthe first direction and an inclined portion 209 a at an end portion inthe second direction of the horizontal portion 209 b, wherein theinclined portion 209 a is extended in a direction where the second rackgear 2052 is overlapped with the first rack gear 2051.

When the mobile terminal is switched from the first state to the secondstate, the rack guide protrusion 20521 may be arranged at the inclinedportion 209 a of the rack guide wall 204 and then slid along theinclined portion 209 a and move along the horizontal portion 209 b.Since the second rack gear 2052 of the first state and the second rackgear 2052 of the second state are different from each other in positionsof the thickness direction, the inclined portion 209 a may be used toguide movement of the thickness direction of the second rack gear 2052.

The rack guide protrusion 20521 may be formed at each of end portions inthe first direction and the second direction of the second rack gear2052, and may be configured symmetrically in the third direction. Sincethe rack guide protrusion 20521 formed at the end portion in the firstdirection and the rack guide protrusion 20521 formed at the end portionin the second direction may move along their respective rack guide rails209 different from each other, the rack guide rails 209 may be disposedin parallel in the first direction as shown in FIG. 14.

Since the rack guide protrusion 20521 is protruded from the second rackgear 2052, as shown in FIG. 14(c), the rack guide rail 209 and the firstrack gear 2051 are not overlapped with each other and do not affectmovement of the first rack gear 2051 even though the pair of rack guiderails 209 disposed in parallel in the first direction are not connectedwith each other.

In more detail, a fastening process of the first rack gear 2051 and thesecond rack gear 2052 will be described with reference to FIG. 15. FIG.15 is a view illustrating a fastening process of the first rack gear2051 to the second rack gear 2052 in the driving unit 200 of FIG. 12.

If the driving unit moves in the first direction a distancecorresponding to the portion where the first rack gear 2051 and thesecond rack gear 2052 are overlapped with each other as shown in FIG.15(a) and thus the end portion in the second direction of the first rackgear 2051 and the end portion in the first direction of the second rackgear 2052 are close to each other, the first rack gear 2051 overlappedwith the second rack gear 2052 disappears, whereby the second rack gear2052 may move to the space where the first rack gear 2051 is arranged.At this time, since the second rack gear 2052 moves along a trackcorresponding to the rack guide rail 209, the second rack gear 2052 maymove along the inclined portion 209 a by forming an oblique slope.

The driving unit 200 may include a pusher 208 pushing the second rackgear 2052 in the first direction to allow the second rack gear 2052 tomove along the inclined portion 209 a, thereby facilitating stateswitching from (a) to (b). If the pusher 208 pushes the second rack gear2052 in the first direction at the end portion in the second directionof the second rack gear 2052 to detach the first rack gear 2051 from itsoverlap portion with the second rack gear 2052, the rack guideprotrusion 20521 of the second rack gear 2052 may move along theinclined portion 209 a of the rack guide rail 209.

The pusher 208 may include an elastic portion 2082 compressed at thefirst state of the second rack gear 2052 and elongated until the rackguide protrusion 20521 moves along the inclined portion 209 a and thenenters the horizontal portion 2082. A pusher block 2081 transferringelasticity of the elastic portion 2082 adjoins the end portion in thesecond direction of the second rack gear 2052.

If the rack guide protrusion 20521 enters the horizontal portion 209 b,the pusher 208 may be arranged to be spaced apart from the second rackgear 2052 as shown in FIGS. 13(a) and 13(b).

The second rack gear 2052 moving along the inclined portion 209 a may befastened to the first rack gear 2051 in parallel and move at the samespeed as that of the first rack gear 2051. At this time, the first rackgear 2051 and the second rack gear 2052 are fastened to each other bycoupling between a first fastening unit arranged in the second directionof the first rack gear 2051 and a second fastening unit arranged in thefirst direction of the second rack gear 2052. If the first fasteningunit and the second fastening unit are fastened to each other, the firstrack gear 2051 and the second rack gear 2052 are configured by one longrack gear 205, and if a force is applied to either the first rack gear2051 or the second rack gear 2052, the first rack gear 2051 and thesecond rack gear 2052 move at the same time.

As shown in (b) of FIG. 15, after the first rack gear 2051 and thesecond rack gear 2052 are connected with each other in series, thepinion gear 202 is engaged with the first rack gear 2051. However, afterthe pinion gear 202 moves in the first direction at a predetermineddistance, the pinion gear 202 transfers force by being engaged with thesecond rack gear 2052 as shown in (b) of FIG. 13.

When the first fastening unit and the second fastening unit are coupledwith each other, the first fastening unit and the second fastening unitmay partially be overlapped with each other. The overlap of the firstrack gear 2051 and the second rack gear 2052 means that the second rackgear 2052 is arranged at a height different from that of the first rackgear 2051 in the thickness direction, and excludes the state that thefirst fastening unit and the second fastening unit are partiallyoverlapped with each other. FIGS. 16 to 21 are views illustratingembodiments of a fastening process of the first rack gear 2051 and thesecond rack gear 2052. In the embodiment shown in FIG. 16, the firstfastening unit of the first rack gear 2051 is arranged at the endportion in the second direction, and the first fastening unit and thesecond fastening unit should form a sawteeth shape of the first rackgear 2051 and the second rack gear 2052 after coupling.

Therefore, some of the sawteeth arranged near the end portion in thesecond direction of the first rack gear 2051 may be omitted to catch thefirst fastening unit and some of the sawteeth arranged near the endportion in the first direction of the second rack gear 2052 may beomitted to catch the second fastening unit. Since the inclined portion209 a of the rack guide rail 209 shown in FIGS. 12 to 15 is overlappedwith the second rack gear 2052 in a direction of the sawteeth surface ofthe first rack gear 2051, the second rack gear 2052 moves from an upperportion to a lower portion on the drawing. Therefore, a portion of thecontinuous rack gear 205 formed by overlap between the first fasteningunit and the second fastening unit, corresponding to the secondfastening unit may be arranged at the upper portion, and the first rackgear 2051 may be arranged at the lower portion.

The first fastening unit in the embodiment of FIG. 16 may include afirst fastening sawtooth 20515 and a fastening groove 2514 disposed toadjoin a first direction of the first sawtooth 10515. The fasteninggroove 20514 has a shape formed by omission of an upper portion of thesawteeth, and connects the first rack gear 2051 with the first fasteningsawtooth 20515.

The second fastening unit may include a second fastening sawtooth 20524arranged at the end portion in the first direction and coupled to beoverlapped with the fastening groove 20514, and a fastening hole 20525into which the first fastening sawtooth 20515 is inserted. In order thatthe second fastening sawtooth 20524 is inserted into the fasteninggroove 20514, the second fastening sawtooth 20524 may have a shapeformed by partial omission of a lower portion. The second fasteningsawtooth 20524 may be protruded upwardly through the fastening hole20525 to configure continuous sawteeh of the rack gear 205.

The first rack gear 2051 and the second rack gear 2052 may includesawtooth portions 20513 and 20523 provided with sawteeth and edgeportions 20511 and 20512 arranged at both sides of the sawtooth portions20513 and 20523. The edge portions 20511 and 20512 may include astructure for guiding slide movement of the rack gear 205, such as astep difference structure for arrangement on the guide wall as shown inFIG. 14(c).

The edge portions 20511 and 20512 may be omitted at the first fasteningunit and maintained at the second fastening unit to form a continuoussurface. Also, as shown in FIG. 16(a), an edge protrusion 20516protruded at the position where the edge portions 20511 and 20512 of thefirst fastening unit are omitted, and an edge groove 20526 formed bypartial omission of the edge portions from the second fastening unit ofthe position corresponding to the edge protrusion 20516 may implement anoverlap fastening structure of the edge protrusion 20516 and the edgegroove 20526. Since the edge protrusion 20516 is arranged in the firstrack gear 2051 and the edge groove 20526 is arranged in the second rackgear 2052, the edge protrusion 20516 and the edge groove 20526 may bearranged to adjoin an opposite side of the sawteeth surface.

As shown in FIG. 16(b), the inclined portion 209 a may be formed at theedge portions 20511 and 20512 of the portion adjacent to the firstfastening unit to guide the second fastening unit of the second rackgear 2052 to exactly move to the first fastening unit of the first rackgear 2051.

As shown in FIG. 17(a), the fastening sawtooth 20515 may partially beomitted (20517) in the third direction and a sawtooth 20527corresponding to the omitted fastening sawtooth portion 20517 may beformed at an opposite side, whereby the first fastening unit should becoupled with the second fastening unit to form one fastening sawtooth20515.

As shown in FIG. 18, the sawtooth portions may be omitted from one ofthe first fastening unit and the second fastening unit, and the edgeportions may be omitted from the other one of the first fastening unitand the second fastening unit and the first fastening unit and thesecond fastening unit may be fastened only by the edge protrusion 20516and the edge groove 20526. Since the edge portions are omitted from thefirst fastening unit on the drawing, the edge protrusion 20516 may beformed in the first fastening unit, and the edge groove 20526 may beformed in the edge portions 20513 and 20523 of the first fastening unit.On the contrary, if the sawtooth portions 20513 and 20523 of the firstfastening unit are omitted and the edge portions 20511 and 20512 of thesecond fastening unit are omitted, the edge groove 20526 may be formedin the first fastening unit, and the edge protrusion 20516 may be formedin the second fastening unit. In this case, the edge groove 20526 andthe edge protrusion 20516 may be disposed to adjoin the sawteethsurface.

According to the embodiment of FIG. 19, the first fastening unit mayinclude first coupling sawteeth 20515 smaller than a plurality ofsawteeth of the first rack gear 2051, and the second fastening unit mayfurther include second coupling sawteeth 20524 provided with a groovecoupled to the first coupling sawteeth, having the same size as that ofthe plurality of sawteeth. If the number of the first coupling sawteeth20515 and the second coupling sawteeth 20524 is increased, a fasteningforce may be enhanced but a stroke may be shortened.

As shown in FIGS. 20(a) and 20(b), the first fastening unit and thesecond fastening unit may include magnets 20518 and 20528 having theirrespective polarities different from each other. The magnets 20518 and20528 having their respective polarities different from each other maybe arranged at the end portion in the second direction of the first rackgear 2051 and arranged at the end portion in the first direction of thesecond rack gear 2052, whereby the magnets 20518 and 20528 may becoupled with each other to configure a long rack gear 205 when the firstrack gear 2051 and the second rack gear 2052 are disposed in series.

Alternatively, as shown in FIGS. 21(a) and 21(b), a coupling member 2053having one end coupled to the first rack gear 2051 and the other endcoupled to the second rack gear 2052 may be used. The coupling member2053 may be bent when the first rack gear 2051 and the second rack gear2052 are overlapped with each other, and may form a straight line whenthe first rack gear 2051 and the second rack gear 2052 are seriallydisposed in parallel in the first direction, whereby the first rack gear2051 and the second rack gear 2052 may move in parallel.

Since the mobile terminal 100 may control a size of a screen ifnecessary, both portability and usability may be fulfilled.

The length of the rack gear 205 may be obtained to enlarge the extendedarea of the mobile terminal.

Serial arrangement or overlap arrangement in a thickness direction of apair of rack gears are automatically performed to facilitate a statechange of the mobile terminal.

The above detailed description is to be considered in all respects asillustrative and not restrictive. The scope of the specification shouldbe determined by reasonable interpretation of the appended claims andall change which comes within the equivalent scope of the presentapplication are included in the scope of the present application.

What is claimed is:
 1. A mobile terminal comprising: a first frame; asecond frame configured to slidably move with respect to the first framein a first direction to switch from a first state to a second state andin a second direction opposite to the first direction to switch from thesecond state to the first state; and a driving unit configured tocontrol a slide movement of the second frame, wherein the driving unitcomprises: a motor coupled to the first frame; a pinion gear rotated bya rotational force transferred from the motor; a first rack gearextended in the first direction and configured to linearly move in thefirst direction or the second direction in accordance with rotation ofthe pinion gear; and a second rack gear disposed to be overlapped withthe first rack gear in a forward or backward direction in the firststate and disposed to release an overlap state with the first rack gearin the second state.
 2. The mobile terminal of claim 1, wherein thesecond rack gear comprises a rack guide protrusion protruding in a thirddirection perpendicular to a moving direction of the second rack gear,wherein a rack guide rail receives the rack guide protrusion, whereinthe rack guide rail comprises a horizontal portion extended in the firstdirection and an inclined portion extended from an end portion of thehorizontal portion to form a slope.
 3. The mobile terminal of claim 2,wherein the rack guide protrusion is formed at each end portion of thesecond rack gear, wherein the rack guide rail is one of a pair of rackguide rails spaced apart from each other in the first direction.
 4. Themobile terminal of claim 2, wherein the rack guide protrusion and therack guide rail are respectively formed in a third and fourth directioneach perpendicular to the first direction of the second rack gear. 5.The mobile terminal of claim 2, wherein the rack guide protrusion movesalong the inclined portion based at least in part on the first rack gearmoving in the first direction to release an overlap state of the firstrack gear and the second rack gear and is arranged at a same height asthe second rack gear in a forward or backward direction when the rackguide protrusion moves along the inclined portion.
 6. The mobileterminal of claim 5, further comprising a pusher for pushing the secondrack gear in the first direction to allow the second rack gear to movealong the inclined portion.
 7. The mobile terminal of claim 6, whereinthe pusher comprises an elastic portion disposed at the end portion ofthe second rack gear in the second direction, wherein the elasticportion comprises a variable length.
 8. The mobile terminal of claim 1,wherein a first fastening unit disposed at an end portion of the firstrack gear in the second direction and a second fastening unit disposedat the end portion of the second rack gear are coupled with each otherto form a continuous rack gear.
 9. The mobile terminal of claim 8,wherein the first fastening unit comprises a first fastening sawtoothdisposed at the end portion of the first rack gear in the seconddirection, and a fastening groove disposed proximate to the firstfastening sawtooth in the first direction, and wherein the secondfastening unit comprises a second fastening sawtooth arranged at the endportion of the second rack gear in the first direction and coupled to beoverlapped with the fastening groove and a fastening hole for receivingthe first fastening sawtooth.
 10. The mobile terminal of claim 8,wherein the first rack gear and the second rack gear each comprise asawtooth portion provided with a plurality of sawteeth and edge portionsarranged at both sides of each respective sawtooth portion, wherein oneof the first fastening unit or the second fastening unit furthercomprises an edge protrusion instead of an edge portion, and a remainingone of the first fastening unit or the second fastening unit furthercomprises an edge groove provided at the edge portion such that thefirst fastening unit and the second fastening unit are fastened by theedge protrusion and the edge groove.
 11. The mobile terminal of claim 8,wherein the first fastening unit further comprises first couplingsawteeth smaller than a plurality of sawteeth of the first rack gear,and the second fastening unit further comprises second coupling sawteethprovided with a groove coupled to the first coupling sawteeth, whereinthe second coupling sawteeth has a same size as the plurality ofsawteeth of the first rack gear.
 12. The mobile terminal of claim 8,wherein the first fastening unit and the second fastening unit eachcomprise magnets having their respective polarities different from eachother.
 13. The mobile terminal of claim 1, further comprising a couplingmember having a first end coupled to the first rack gear and a secondend coupled to the second rack gear, wherein the coupling member is bentwhen the first rack gear overlaps the second rack gear, wherein thecoupling member forms a straight line in the first direction when thefirst rack gear and the second rack gear are disposed in parallel in thefirst direction.
 14. The mobile terminal of claim 1, wherein a sawteethpitch of the first rack gear is equal to a sawteeth pitch of the secondrack gear.